The microscopic expl. of how light is slowed in materials

[DanMP]

In wikipedia I found:

At the atomic scale, an electromagnetic wave's phase velocity is slowed in a material because the electric field creates a disturbance in the charges of each atom (primarily the electrons) proportional to the electric susceptibility of the medium. (Similarly, the magnetic field creates a disturbance proportional to the magnetic susceptibility.) As the electromagnetic fields oscillate in the wave, the charges in the material will be "shaken" back and forth at the same frequency.[1]:67 The charges thus radiate their own electromagnetic wave that is at the same frequency, but usually with a phase delay, as the charges may move out of phase with the force driving them (see sinusoidally driven harmonic oscillator). The light wave traveling in the medium is the macroscopic superposition (sum) of all such contributions in the material: the original wave plus the waves radiated by all the moving charges.

If what I underlined is correct, it means that from one incident photon we will get at the other end countless similar photons, as the "shaken" charges radiate "their own electromagnetic wave" (photons, right?). This sounds like light amplification, but the explanation is about any transparent material not about lasers. And the "amplification" would increase with the width/depth of the material (glass, water, etc.), because there are more atoms ready to "produce" new photons. We know that light doesn't get brighter when crossing through glass, water, etc. So what is wrong?

(I addressed this problem in another tread, but the answers I got from DrClaude were far from satisfactory. And then he closed the tread. Not so friendly forum ...)

 

[sophiecentaur]

answers I got from DrClaude were far from satisfactory. And then he closed the tread. Not so friendly forum ...)

If what I underlined is correct, it means that from one incident photon we will get at the other end countless similar photons, as the "shaken" charges radiate "their own electromagnetic wave" (photons, right?).

If it really were like that and if atoms absorb and re-emit photons, the path of light through a transparent medium wouldn't allow a coherent image to be formed because the absorption/emission process would introduce a variable phase and the wavefront would become diffuse. Optical instruments would just not work.

That effect does occur in gases with isolated atoms and the effect is to produce an absorption spectrum, consisting of dark lines in a normal white light continuous spectrum. The effect is not coherent; though.

(I addressed this problem in another tread, but the answers I got ********** were far from satisfactory.

It strikes me that you're not satisfied because you didn't actually understand what was written. Frankly, although it can be fun to make up one's own Physics explanations, those explanations can easily be hopelessly wrong. This is not cutting edge Science and the standard models are usually pretty good. So why not stick to them?

 

[berkeman]

(I addressed this problem in another tread, but the answers I got from DrClaude were far from satisfactory. And then he closed the tread. Not so friendly forum ...)

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